Examination for diabetic patients with complications - Photo: BVCC
Vitamin B12 is absorbed mainly from animal protein sources, the liver is where 90% of the body's total vitamin B12 is stored.
Vitamin B12 deficiency causes hematological and neurological diseases. Vitamin B12 deficiency in type 1 diabetes is mainly related to autoimmune conditions. In type 2 diabetes, it is mainly related to the use of metformin - a blood sugar lowering drug.
33-45% of diabetic patients are deficient in B12
Doctor Nguyen Thi Ho Lan, Central Endocrinology Hospital, warns that polyneuropathy in diabetic patients can be caused by many reasons, including vitamin B12 deficiency.
Dr. Lan analyzed that pernicious anemia due to chronic autoimmune gastritis often occurs in patients with type 1 diabetes. Chronic autoimmune gastritis and pernicious anemia occur in about 1-2% of the general population, in patients with type 1 diabetes this rate increases 3-5 times.
A study in southern India of 90 patients with type 1 diabetes found that 45.5% of subjects had low vitamin B12 levels.
The cause of this condition, according to Dr. Lan, is that type 1 diabetic patients often have autoantibodies to visceral factor (AIF) and parietal cell antibodies (PCA).
PCA inhibition of intrinsic factor leads to pernicious anemia (10 times more common in type 1 diabetics than in non-diabetic patients). The presence of AIF inhibits vitamin B12 absorption and interferes with vitamin B12 transport to the ileum.
Additionally, celiac disease is a long-term autoimmune disorder that primarily affects the small intestine and occurs quite commonly in 1-16% of patients with type 1 diabetes, compared with 0.3-1% of the population.
Ingestion of gluten and other proteins found in wheat and other grains has been noted as a trigger for the condition in genetically susceptible people.
Due to the associated pathology, patients often have growth retardation, chronic diarrhea, and anemia due to poor absorption of micronutrients (mainly folate, vitamin B12).
In patients with type 2 diabetes, metformin is a known cause of vitamin B12 deficiency. A Finnish study of 1,048 elderly people aged 65-100 years found that the overall prevalence of vitamin B12 deficiency was 12.1%.
Usually, reduced vitamin B12 absorption begins in the fourth month after drug use and vitamin B12 deficiency in type 2 diabetic patients manifests itself within 5-15 days due to rapid depletion of large hepatic stores.
Studies evaluating patients with type 2 diabetes taking metformin have reported rates of vitamin B12 deficiency ranging from 5.8 - 33%.
Blood sugar control is very important for diabetic patients - Illustration photo
Correct supplementation avoids nerve damage
According to Dr. Lan, vitamin B12 deficiency accompanied by increased homocystysteine in the blood and high MMA levels (Methylmanonic Acidemia - MMA) is a genetic metabolic disorder. Patients with metabolic defects in certain proteins and fats (lipids) have been noted to be one of the causes of sensory polyneuropathy in diabetic patients.
Worsening of diabetic neuropathy has also been noted in patients with vitamin B12 deficiency.
Vitamin B12 replacement has been shown to improve symptoms in patients with severe diabetic neuropathy. A meta-analysis of data showed that when used alone or in combination with a vitamin B complex, there was a significant improvement in symptoms such as pain and paresthesia.
Three studies also noted an improvement in autonomic symptoms with the use of vitamin B12 alone. Similar positive findings regarding pain and paresthesia were also noted with vitamin B12 in an Iranian clinical trial of 100 patients with diabetic neuropathy.
Treatment of vitamin B12 deficiency does not differ regardless of the cause. All patients with vitamin B12 deficiency should receive primary treatment with oral or parenteral vitamin B12 replacement. Both routes have been shown to improve hematologic and neurological function regardless of the cause of deficiency.
In adult patients with type 2 diabetes, intramuscular injection of vitamin B12 or oral administration of 1000 µg daily for 1 week, then once weekly for 4 weeks is sufficient to correct vitamin B12 deficiency.
In young patients with type 1 diabetes who are vitamin B12 deficient, 100 µg should be given intramuscularly or orally daily for 1 week and then monthly. In severe cases, 1000 µg/day for 1 week, followed by the same dose every week for 1 month and then monthly.
For patients without diabetes, the optimal supplemental dose of vitamin B12 has not been determined. However, Dr. Lan recommends consuming foods rich in vitamin B12 such as liver, eggs, meat, fish, whole grains...
Foods rich in vitamin B12 that diabetic patients should supplement - Illustration photo
Several studies have shown that patients with type 2 diabetes are at increased risk of vitamin B12 deficiency.
Therefore, the American Diabetes Association (ADA) recommends that patients with diabetic neuropathy undergoing treatment should have their vitamin B12 levels monitored annually.
Supplementing vitamin B12 through diet or taking vitamin B12 supplements such as meat, liver, milk and eggs can help people with type 2 diabetes maintain nerve function and support blood sugar control.
However, it should be noted that vitamin supplementation is not a treatment for diabetes. Therefore, when wanting to supplement any vitamins, patients should consult a doctor or pharmacist" - Dr. Ho Lan emphasized.
Source: https://tuoitre.vn/bo-sung-vitamin-b12-tranh-ton-thuong-than-kinh-o-nguoi-benh-dai-thao-duong-20241014220340823.htm
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